Deformation behavior of a PM A16013/15SiCP composite sheet at elevated temperature

The elevated temperature deformation behavior of an A16013/15SiC(P) composite sheet was investigated by uniaxial tensile tests at temperatures ranging from 723 to 853 K and at initial strain rates between 1.67 x 10(-3) and 1.67 x 100 s(-1). The strain rate sensitivity exponent was found to be approximately 0.17 which was apparently below that of a superplastic material. A maximum elongation of similar to 177% was obtained at an initial strain rate of 6.67 x 10(-1) s(-1) and at a temperature of 773 K. The apparent activation energy was calculated to be approximately 370 kJ/mole which is much higher than that of its unreinforced counterpart. The fracture surface morphology showed a large amount of localized plastic deformation in the aluminum matrix and numerous large cavities. The experimental results were compared with that of a high-strain-rate superplastic A16061/20SiC(W). It was considered that premature failure at the reinforcement/matrix interfaces was the main reason for the A16013 composite not showing superplastic properties. (C) 1999 Elsevier Science B.V. All rights reserved.